The research plan presented is designed to determine the properties of the components of hormonally-responsive adenylyl cyclase in the rabbit corpus luteum. The components to be determined are the catalytic component C, the guanine nucleotide regulatory component N, and receptors for gonandotropins and catecholamines. Through the use of reconstitution assays, receptor-binding assays and receptor transfer, the interactions among the components responsible for irreversible activation of adenylyl cyclase by luteinizing hormones (LH) will be determined as well as the reactions responsible for deactivation of the LH-activated enzyme system. Changes in the subcellular distribution of adenylyl cylcase components will be compared after treatment with agents known to shorten corpus luteum lifespan and concurrently derange LH stimulation of adenylyl cyclase. The agents to be tested are human chorionic gonadotropin, prostaglandin F2Alpha and gonadotropin-releasing hormone. Results obtained will shed new light into the mechanisms involved in regulation of corpus luteum function and should help the development of contraceptives designed to alter luteal functon in early pregnancy.